The invention concerns a method and a system to process document data streams. An AFP print data stream is prepared for output to a print device. Such a preparation typically occurs in computers that printer-adaptively process print files or print data from user programs. The document data or print data are converted into an output stream of a specific print data language such as, for example, AFP® (Advanced Function Presentation), Printer Command Language (PCL™) or Post Script™.
In large-scale computer centers, the print data is typically compiled or collated (spooling event) in a host computer (main frame), and from this print tasks (jobs) are generated that are adapted for output on high-capacity printing systems, such that the high-capacity printing systems can be temporally, optimally used at capacity in the production operation. They can thus largely be used in continuous operation.
Such high-capacity printing systems, with print speeds of approximately 40 DIN A 4 pages per minute up to over 1000 DIN A 4 pages per minute, are, for example, specified in the publication “Das Druckerbuch”, published by Dr. Gerd Goldmann (Oce Printing Systems GmbH), edition 4C, October 1999, ISBN 3-000-00 1019-X. In chapter 12 (pages 12-1 through 12-18) of this publication, the print server system known under the same PRISMA PRO® is specified which serves in production printing environments to prepare print data streams.
A typical print data format in electronic production printing environments is the format AFP (Advanced Function Presentation), which, for example, is specified in the publication Nr. F-544-3884-02 by the company International Business Machines Corp. (IBM) with the title “AFP Programming Guide and Line Data Reference”. In this publication, the specification for a further data stream with the designation “S/370 Line-Mode Data” is also specified. The print data stream AFP was further developed into the print data stream MO:DCA, which is specified in the IBM publication SC31-6802-04 with the title “Mixed Object Document Content Architecture Reference”, and that likewise is designated as an AFP data stream. What are known as object containers (that are designated as MO:DCA objects), which comprise object data, are provided in the AFP specification. The object data can thereby be arbitrary data that does not have to correspond to the AFP specification. Further details of Objects Containers are specified in the publication SC31-6802-05, on the pages 93 through 95. Further details of this data stream, in particular the use of structured fields, are specified in U.S. Pat. No. 5,768,488.
Methods and systems are specified in U.S. Pat. No. 5,727,220 and U.S. Pat. No. 5,680,615, in which objects of a document belonging together are processed via a structured data stream such as MO:DCA or IPDS.
The contents of the publications and patent applications cited above are hereby included by reference in the present specification.
In the output of print data in high-speed print applications (which, for example, are applied in computer centers or also in print centers for what is known as PoD (Printing on Demand)), the print data are specially prepared so that they can be processed as quickly as possible in the print production environment and ultimately can be transfer printed on the recording medium. The data preparation thereby occurs primarily with regard to the print outputs meeting specific presentation requirements of the end customer (reader of the printed information).
In the preparation of document data streams for output on an output device, whereby the document data stream is transferred from a first computer to a second computer, and the document data stream comprises document data with which a font is associated, it is sometimes necessary to replace a font that is set in the document data stream with another font. This is in particular true for document data streams that operate with what are known as resources, whereby corollary or secondary document data such as fonts, forms and the like are stored in the resources. Some reasons why a conversion of font information is necessary are the various font technologies that are available (raster fonts or vector fonts) on output devices (such as printers), the various font collections that are available on output devices (for example, what are known as printer-resident fonts), various operating system environments (such as MVS, VSE, Linux, Windows, AS/400, and so forth), and copyright problems with specific fonts.
In various system environments that use the document data stream Advanced Function Presentation, a certain support for conversion of fonts is already offered today. In some products, the conversion algorithms are firmly anchored in the document processing software. In other products, external tables are available with which the user can control the conversion.
With the known methods and systems, the problem exists that, when a document data stream is given that requires a specific font conversion, and a complete collection of resources for this document processing job is available, the resource collection and the document output can be significantly different depending on which platform and with which application software the document processing job is processed.
The conversion of fonts is generally also then used by installations when standardized font collections are shared between a plurality of applications, systems and sites or locations. In this case, the font resources in all servers are available and are not sent together with the application as part of the inline resources when these move from a first environment to another environment. Instead of this, the applications are tied to a global resource identification (GRID) that is associated with each font. The GRID identification is used in order to search through conversion tables in order to find what are known as the “code page” and the character set that best matches the target output device.
In the processing of Advanced Function Presentation data streams, the risk exists that a document data stream that requires a character conversion produces different results depending on which environment is used to prepare the document data stream. This problem has already existed for years, however it became critical due to the increase in distributed printers, electronic archives and data stream converters.